Portable hand-operated tube bending tool



Sept. 30, 1947. D. MGINTOS H 2,428,237

PORTABLE HAND-OPERATED TUBE BENDING TOOL Filed July 15, 1944 2 Sheets-Sheet l I N V EN TOR.

Sept. 30, 1947. D. M'clNTOSH l 2,423,237

PORTABLE HAND-OPERATED TUBE BENDING TOOL Filed July 15, 1944' 2 Sheets-Sheet 2 IN VEN TOR.

fogeri [3117015223672 Um/my Patented Sept. 30, 1947 UNITED STATES PATENT OFFICE PORTABLE HAND-OPERATED TUBE BENDING TOOL Application July 15, 1944, Serial No. 545,105

1 Claim. 1

My invention relates to tube benders and particularly hand service tools which can be carried about in the kit of a serviceman and which are adapted especially to bending relatively thinwalled tubing of a specified size.

Among the objects of my invention is to provide a new and improved hand operated tube bender for thin-walled tubing which is easy to manipulate and relatively inexpensive to manufacture.

Another object of my invention is to provide a new and improved hand operated tube bender wherein a relatively movable lever can be applied to or separated from a relatively stationary part at any position of one with respect to the other.

Still another object of my invention is to provide a new and improved tube bender wherein a movable lever is provided with a double rip upon a stationary member so that retention of one with respect to the other is balanced in order to minimize any lack of adjustment which might occur by reason of the wearing of the moving parts after a period of service.

A further object of my invention is to provide as a special feature in a nominal two-piece hand tube bender a means of attachment for the mov ing parts of one with respect to the other such that the parts can be freely separated at the initiation of a bending operation but which become inseparable throughout subsequent phases of the bending operation so that the parts may not become inadvertently separated while a bend is being made or when the parts are coupled together and tossed into a tool kit.

- A further object still of my invention is to provide a two-piece bending tool wherein the movable part has a connection at both sides to the stationary part and a window aperture so arranged that the degree of bend can be read without it being necessary to separate one part of the tool from the other. 7

Another object is to provide a hand operated tube bender comprising a pair of levers which are 50 connected together that the levers extend in opposite directions from the bending area when the bend is being started so that the most desirable mechanical advantage can be had at the initiation of the bending operation.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of m device whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claim and illustrated in the accompanyin drawings, in which:

Figure 1 is a side view of the bending elements of the device with a tube inserted showing the relative position of the parts at the start of a bending operation.

Figure 2 is a view similar to Figure 1 showing the relative position of the parts after a bend of has been made.

Figure 3 is an end view partly in cross-section taken on the line 3-3 of Figure 1.

Figure 4 is a top View with the parts in the relative positions shown in Figure 2.

Figure 5 is a side view of the complete device drawn to a smaller scale showing the parts in the relative position they would have at completion of a bend.

Figures 6, '7 and 8 are side views similar to Figures 1, 2 and 5 showin a modified form of the device.

One of the aims attempted in the construction of a'hand service tube bender is to provide a tool which is so simple in its construction and manner of operation that it will not become misaligned or have its adjustment disturbed when it is given the customary hard usage which a mechanic is usually inclined to give tools which he carries about from day to day in his service kit.

Tools of this kind likewise must be as light in weight as would be commensurate with the required strength so that they do not become a burden for a mechanic to carry about when he makes service calls in the field. It is highly desirable to have these tools as simple in construction as they can be made so that a different tool can be carried for each different size without the expense or weight involved becoming unnecessarily great, It must also be borne in mind that these requirements must not sacrifice the accuracy and ruggedness necessary in a tool of this kind. Bench tools which are common to the prior art are not suitable for being carried about in the field.

In the drawings there is shown a tube holding member including a relatively stationary receiving lement or bending block [9 which determines the degree of curvature of the bend which is to be made in the tubing. The bending block shown is relatively semi-circular having one fiat side 12 from which'a handle It extends. On the rounded portion of the bending block there is provided a groove 53 semi-circular in cross-section which has substantiallythe same diameter as the diameter of the tube which is intended to be bent with the device. A clamp I6 is shown rotatably movable upon the handle M at a reduced neck l8 and the clamp occupies a position between a shoulder 20 on the handle and the fiat face 12 of the bending block. It will be noted that the clamp rotates about the axis of the handle it. The clamp has a hook-like element 22 shown in' Figure 3 in a position engaging a length of tube 24. In the same figure the clamp is shown in a released position by the dotted outline 22'.

A tube bending member is shown cooperable with the tube holding member and includes a handl 30 which is provided with a bending and forming element 32 comprising an elongated portion having an elongated groove 34 of cross-sectional curvature complementary to the groove in the bending block Ill.

The head of the tube bending and forming element is fork-shaped and comprises lateral extensions 36 and 38 which are spaced apart a distance slightly greater than the thickness of the bending block [0. At the sides respectively of the bending blocks are raised bosses 4D and 4| having such a height that they fit snugly between the side faces of the forming element. This prevents the faces from scraping in contact with the flat side faces of the bending block.

The lateral extensions of the fork are provided with slots 42 and 44, respectively. A shaft 46 extends laterally through the bending block at the center of the radius of curvature and protrudes outward a distance slightly in exces of the thickness of the extensions.

On the bending element is shown a scale A? graduated in 15 intervals from to 180. one of the extensions is a window 50 having an indicating mark 52 at one edge adapted to coincide with the graduation of the scale visible through the window.

In the modified type of connection shown in Figures 6, 7 and 8 a shaft 48" is shown at the.

center of the radius of curvature of the bending blocks having a fiat face 49 at one side. In this form the lateral extensions of the bending element each have a slot 56 substantially equal in width to the distance between the flat 49 on the shaft and the opposite curved side. At the inside end the slot is widened out so that it is substantially round and has the same diameter as that of the shaft.

In the operation of the device as best seen in Figures 1 and 2, the tube 24 is first placed in the position shown in Figure 1 and the clamp I6 is then rotated into the position there shown so that it engages the tubing. This is done before the bending and forming element has been applied.

After the tube has thus been engaged the forming element is brought into the position shown in Figure 1 and the shaft 46 is slid into the slot 42. This is at 0 of bend as shown in Figur 1 and the groove in the bending and forming element lies against the outside surface of the tubing 24. In this position the handles [4 and 30 extend substantially in opposite directions from the bending block at the start of the bend. The handles are then rotated one with respect to the other in a direction which will permit them to assume the relative positions shown in Figure 2. Figure 2 shows the position of the parts at the completion of a 90 bend as indicated by the registration of the index mark in the window. If it is a 90 bend which is needed the parts of the tool can be immediately disengaged by merely unhooking the side elements from the shaft 46 without it being necessary to reposition either of the members.

If by chance this bend should be insuflicient, the tube can be reinserted into the relatively stationary element at any tim and the bending and forming element reapplied to the shaft and a further bending efiected. The tubing can be bent further to a 180 bend with the parts in the relationship shown in Figure 5.

In the modified version of the tool shown in Figures 6, 7 and 8, the forming member cannot be separated from the holding member except when the parts occupy a certain predetermined relationship, After the slot 55 has been slid over the shaft while parallel to the face of the fiat 49 the parts are locked together when they are rotated. To separate them in order to remove a bent tube they should again be rotated until the side of the slot is parallel to the fiat on the shaft, Return to this position places the bending levers in the relative positions shown in Figure 6 Customarily, the fiat side of the shaft 46' is so positioned with respect to the direction of the narrow slot 56 that they can be hooked together at the start of the bending operation. When the parts are thus engaged they will maintain engagement of one with respect to the other so long as the tube continues to be bent. They must always be returned to the initial position in order to uncouple the two parts of the device. The same cou pled relationship will remain effective equally well when there is no tube in the bender and thus will prevent the parts from becoming separated while the tool is being carried about in a tool kit.

There has thus been provided a two-piece bending tool wherein the movable parts have been kept to the relativ minimum and wherein the wearing parts are balanced on opposite sides of the tube so that the parts will remain in adjustment in order to compensate for wear which will invariably occur as the tool continues to be used.

Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claim any modified forms of structure, or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

A portable, hand operated bending tool for tubing comprising a pair of members to be grasped and supported one in each hand of a Workman, one of said members including a bending block having a substantiall semicircular edge with a tube-receiving groove therein, a handle lever extending from the side of the block remote from the groove, a clamp movably mounted on the handle lever adapted to engage the tube for holding it in the tool and a shaft at the center of curvature of the semicircular edge in the bending block extending laterally outwardly therefrom at both sides, said shaft having a flattened side portion extending parallel with the handle lever and the other of said members including a lever arm, a grooved tube bending element at one end of the arm for cooperation with the bending block in performing a tube bending operation, lateral extensions overlying the sides of the bending element and adapted to receive the bending block therebetween when said members are assembled for performing a bending operation, and a slot opening through the forward edge of the lateral extensions and extending rearwardly inwardly generally parallel with the lever arm, said slots having at the outer ends thereof a width greater than the distance diametrically of the shaft at the fiat portion thereof and smaller than the diameter of the shaft and having an inner end substantially equal to the diameter of the shaft whereby said members may be assembled or disassembled by relative movement of said members in a direction generally longitudinally of said first named member when said members are in a position extending generally in opposed directions, said members being retained against dis- Number Name Date assembly in all other relative angular positions. 2,083,483 strezofi June 8, 1937 1,824,026 Little Sept. 22, 1931 ROBERT MCINTOSH' 5 2,171,907 Beehler et a1 Sept. 5, 1939 2,232,819 Abramson et a1 Feb. 25, 1941 REFERENCES CITED 1,879,199 Grimes Sept. 27, 1932 The following references are of record in the 2,127,135 Parker Aug. 16, 1938 file of this patent: 2,345,102 Dick Mar. 28, 1944 UNITED STATES PATENTS 10 FOREIGN PATENTS Number Name Date Number Country Date 1,438,952 Evans Deg. 19, 1922 417,656 Great Britain Oct. 3, 1934 

